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泥石流灾害是我国东南地区引起群死群伤的主要自然灾害,目前对其发育规律和区域预报的研究程度还较低.基于浙江省小流域泥石流地质灾害调查评价成果数据,开展沟谷泥石流发育特征和时空分布规律研究,研究表明,浙江省泥石流发生时期集中在台汛期和梅汛期,其中台汛期发生的泥石流占总数的70.1%,梅汛期占27.4%,可见台风诱因显著;泥石流在浙江省三大降雨区,即台风雨主控区、梅雨主控区和梅台雨兼容区的空间分布具有明显差异性,总体上东南沿海一带台风雨控制区分布密度要大于西部和北部地区,而梅汛期发生泥石流则比较明显集中在西部地区.在此基础上,分别求取了梅汛期和台汛期的浙江省东南地层区和杨子地层区引发泥石流的降雨阈值;选择泥石流易发程度区划图、24h预报雨量和前期有效降雨量3个因子,以小流域作为评价单元,基于可拓理论方法,构建了泥石流危险性区域预报模型.采用灾害强度R值和危险性等级面积百分比累加-泥石流频度百分比累加曲线两种方法,以2004年“云娜”台风期间和2006年6月份梅雨期发生的泥石流灾害样本开展模型合理性检验,证明预测结果合理.
Debris flow disaster is the major natural disasters that cause mass death in southeastern China, and its current research on the law of development and regional forecasting is still low.According to the data of the investigation and evaluation of debris flow geological hazards in Zhejiang small watershed, The research shows that the occurrence of debris flow in Zhejiang Province is concentrated in the flood season and the plum flood season, in which the debris flow occurred in the flood season accounted for 70.1% of the total flood season, plum flood season accounted for 27.4%, the typhoon incentives can be obvious; debris flow in Zhejiang Province, The spatial distribution of rainfall areas, ie typhoon main control zone, Meiyu main control zone and Meitai rain compatible zone are obviously different. Generally speaking, the distribution density of typhoon control zone in the southeast coast is greater than that in western and northern regions, Debris flow is more obviously concentrated in the western region.On the basis of this, the rainfall threshold of debris flow caused by the southeastern stratum of Zhejiang Province and Yangzi stratigraphic zone in the plum-flood season and the flood season of Taiwan is calculated separately. Rainfall and pre-effective rainfall three factors, a small watershed as the evaluation unit, based on extension theory, The debris flow hazard regional prediction model was built.Considering the cumulative percentage of debris flow R value and hazard grade percentage cumulative percentage of debris flow frequency percentage, The debris flow disaster occurred in the model to test the rationality of the model to prove that the forecast result is reasonable.